1. Field of the Invention
This invention relates to a vibration switch, more particularly to a vibration switch with an axially extending deflectable electric contact body which has two ends anchoring on two side walls of a housing and an intermediate portion that is deflectable so as to make an electrical connection between two electric contact terminals.
2. Description of the Related Art
FIGS. 1 to 3 show a vibration switch 1, which is disclosed in U.S. Pat. No. 6,545,235 B1 granted to the applicant of the present invention. The vibration switch 1 includes an electrically conductive housing 11, a coil spring 12, and first and second electric contact terminals 114,14. The housing 11 defines an accommodation chamber 112 therein. The first electric contact terminal 114 extends downwardly from a side wall 1122 of the housing 11. The second electric contact terminal 14 passes through an insulating plug member 13 fitted in an open end 1121 of the housing 11 so as to extend into the accommodation chamber 112. The coil spring 12 has an anchoring end 121 which anchors on a stem portion 113 secured on the side wall 1122, and a deflectable segment 123 which extends from the anchoring end 121 towards the second electric contact terminal 14 to terminate at a contact terminal end 122. By virtue of the biasing force of the deflectable segment 123 that acts against the weight thereof, the contact terminal end 122 is held in such a manner as to surround the second electric contact terminal 14. As shown in FIG. 3, once the housing 11 is jerked by means of a force (F), the contact terminal end 122 is deflected radially as a result of an inertial force of the deflectable segment 123 so as to contact the second electric contact terminal 14, thereby making an electrical connection between the first and second electrical contact terminals 114,14. The vibration switch 1 can provide a stable electrical connection between the electric contact terminals 14,114. However, since only the anchoring end 121 of the coil spring 12 is secured relative to the housing 11, the contact terminal end 122 tends to droop, and may undesirably contact the second electric contact terminal 14, thereby resulting in a contact error.
The object of the present invention is to provide a vibration switch in which a deflectable electric contact body can be supported firmly so as to minimize undesired contact of the contact body with an electric contact terminal.
According to this invention, the vibration switch includes a housing, first and second electric contact terminals, and a deflectable electric contact body.
The housing is adapted to be mounted on a support in an upright direction, and has first and second side walls spaced apart from each other along an axis in a longitudinal direction transverse to the upright direction, and a surrounding wall interposed between and cooperating with the first and second side walls to confine an accommodation chamber thereamong.
The first electric contact terminal has a first connecting end which is adapted to be connected to the support, and a first contact end which extends from the first connecting end to confront the accommodation chamber.
The second electric contact terminal is disposed to be electrically insulated from the first electric contact terminal, and has a second connecting end which is adapted to be connected to the support, and a second contact end which extends from the second connecting end into the accommodation chamber proximate to the second side wall. When the vibration switch is in a stable position, the second contact end is electrically insulated. The second contact end is spaced apart from the first contact end within the accommodation chamber.
The deflectable electric contact body is disposed in the accommodation chamber, and has first and second anchoring ends which are opposite to each other in the longitudinal direction and which are disposed to anchor on the first and second side walls, respectively, and an intermediate portion which is interposed between the first and second anchoring ends. The intermediate portion is made from a deflectable material, and includes a deflecting segment, and first and second deflected segments that flank the deflecting segment and that are respectively proximate to the first and second anchoring ends so as to be deflected with the deflecting segment in the same direction. The deflecting segment is configured in such a manner as to acquire a biasing force such that, by virtue of the biasing force that acts against weight of the deflecting segment, the first and second contact ends are held in the stable position, and such that, when the housing is jerked out of the stable position, the deflecting segment, together with the first and second deflected segments, is deflected in a direction radial to the axis as a result of an inertial force thereof, thereby bringing at least one of the deflecting segment and the first and second deflected segments into electric contact with at least one of the first and second contact ends.